Well, the Jewish calendar is one system that does not use AD as the "0" and is, traditionally, lunar. Muslim calendars also may use Mohammad and the founding of Islam as a starting date. Hopefully someone will be able to add more, my source would be I have had some Jewish schooling and a few history courses covering the Arabic empires.

The reason why the Gregorian system is so ubiquitous is because many western nations are historically Christian, and have been using the calendar for hundreds of years (with some exceptions such as Russia which used the older Julian calendar until as recently has the early 20th century). When western nations grabbed colonies and created empires they spread their calendar as well, and in the east nations like Japan westernized, adopting the western calendar system to be more in line with the western powers they were competing with.

The Gregorian calendar, in short, spread with European influence.

It is of note that dating from the birth of Jesus was not the standard in the west until the 8th c. Up until this point, it was usual to give the date by the consular year of the reigning Roman emperor (ex. "In the consulship of prince Theodosius").

This finally fell out of favor under the Carolingians for what should be obvious reasons.

In Japan, in situations in which foreigners are not likely to run into it and be confused, they sometimes use era names which have recently been based on the "reign name" of the current emperor. This year is Heisei 26.

The Japanese still date many official things by the year of the Emperor's reign- so currently we're in the year Heisei 26.

And in North Korea it's Juche 103- they count 1912, the year of Kim Il Sung's birth as year 1. (Though they always add the western year as well.)

hi! You'll find more examples in this section of the FAQ

http://www.reddit.com/r/AskHistorians/wiki/calendars#wiki_other_dating_systems

There are groups of Maya that still use the Long Count and 52-year cycle.